Merge github.com:grpc/grpc into error

.travis.yml

include/grpc/impl/codegen/port_platform.h

package.xml

src/core/ext/client_config/lb_policy.c

src/cpp/server/server_posix.cc

src/csharp/Grpc.Core.Tests/Internal/AsyncCallTest.cs

src/csharp/Grpc.Core/IAsyncStreamReader.cs

src/csharp/Grpc.Core/Internal/AsyncCall.cs

src/csharp/Grpc.Core/Internal/AsyncCallBase.cs

src/objective-c/tests/Podfile

src/objective-c/tests/RemoteTestClient/RemoteTest.podspec

src/objective-c/tests/Tests.xcodeproj/project.pbxproj

src/objective-c/tests/build_tests.sh

src/python/grpcio/grpc/__init__.py

src/python/grpcio/tests/tests.json

src/python/grpcio/tests/unit/_api_test.py

src/python/grpcio/tests/unit/_from_grpc_import_star.py

src/python/grpcio/tests/unit/_metadata_test.py

templates/package.xml.template